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TorqueLover

08 wr 450F - power?

6 posts in this topic

hey all,

so am back to thumpertalk after a long hiatus of riding non-yamahas....mainly consisting of ktm 2 stokes ,cr 500af's...and zx10r superbikes...but have decided to get another yamaha for a comp based enduro/dual sport...due to the fact i loved my 02 yz426F...

wanted to get a new ktm 530, but all the engine problems i have herd on ktmtalk have made me fold...pay 11K canadian and have to rebuild or repair the bike with as little as 2000 km...not so great...

have owned a plated 02 yz426F with a baja designs kit, and loved the bike except the tall first gear, and close ratio gears in the last 4 gears...if i geared it to cruise at 50mph,(15-47)the 1st gear useless in the woods or tight trails,so i settled on 14-47...but power...it had enough for me...stock becides air filter de-screen and jd jet kit and bk and oring mod on carb...no bog...just hard pulling torqy engine...perfect

so i found a 08 wr450f, plated with dual purpose kit with 500km on it...stock 13-50 gearing...test road it and found the power decent on bottom,the previous owner was a co-worker and was anal on maintance, and couldnt handle the bike...mostly trail ridden.... but it signs off badly at mid /top...and it seemed like the engine wasnt under load enough,had to be in 3rd gear to have any pull... that coupled with the porr top end of the engine...and therefore didnt pull in low gears...and i was going to need it to cruise at 50mph...so gearing was needed anyway

mods done by origonal owner

- gytr jetting kit and ais blockoff kit

- grey wire removal, and yz throttle stop

- 07 yz 450f silencer

- airbox snorkel removed

what i did so far

- 14-45 gearing

- de-screened air filter cage, and added a twin air filter

- put another 700km using dino yamaha oil, then switched to a pc racing stanless oil filter and 7100 motul synthetic oil...

the bike runs very good after the gearing and air filter mods, finally has some load on the engine...but i still feel it needs more...am planning on using some slp flowrites in the airbox, jd jetting kit, a full exhaust and a quickshot 3...

do those powerwings or powernows actually do anything? what about the boyssen powerbowls>?

would this give me the thrust i am looking for, or will i have to add a 03 or 06 yz 450f or hotcams exhaust cam?

also, looking for a exhaust with max hp gains, regardless of loudness...what would be a good choice?

any feedback would be great...basicly looking for yz or better thrust with the wr transmission for when i have to link up trails on the street...

thanks again

Paul Brinston

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After reading your mods listed above, I would suggest a 2006+ YZ OEM stock header to go with your YZ silencer.

The diameter of the YZ header pipe is much bigger than the WR. This may give you a better exhaust flow, and work well with your other mods.

I tried a full OEM YZ exhaust on my WR, and noticed the bike rev'd out much faster and moved the power from low-to-mid range to all top end power.

Ended up going back to the stock WR exhaust, because the YZ system was just too loud for my type of riding.

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Forget teh powernows, powerwings, powerbowls, unless you just want to slow your bike down or waste money. Do not get a quickshot3 either.

Get the JD kit though if you have all the parts fro the GYTR kit, you should not need th JD one. Get the jetting right, as it sounds like it is not.

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thanks guys, i havent touched the carb yet, and was just going to send it to zip ty racing this winter for carb mods...

but the pilot jet must be big on the gytr jetting kit cause it only runs decent if you only unscrew the mixture screw 1/8 of a turn from fully seated....and still has a bad bog or the bike will shut off it you apply the throttle too fast...but still ridable...

anyone have a zip ty modded carb on there wr?

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thanks guys, i havent touched the carb yet, and was just going to send it to zip ty racing this winter for carb mods...

but the pilot jet must be big on the gytr jetting kit cause it only runs decent if you only unscrew the mixture screw 1/8 of a turn from fully seated....and still has a bad bog or the bike will shut off it you apply the throttle too fast...but still ridable...

anyone have a zip ty modded carb on there wr?

The GYTR 175 main is definately too big. A 165 or 168 depending on temp and elevation should do.

And that 50 pilot is way too fat as well, try a 45 or 48.

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